Painting walls is nowadays often done with a "paint gun" both to save time, as compared to brushes and rollers, and also to provide a smoother finish.
Preparing a wall for such spray painting involves concealing items, such as electrical switches, etc., as mentioned above. Till now the usual means of concealment has been masking tape, the latter has many well-known disadvantages:
(1) it is time-consuming to apply; PA1 (2) there is a danger of electric shock when the tape is applied with a knife. PA1 (3) the tape tears easily; PA1 (4) residual dust in the electrical box may be blown out by the paint gun; (5) the wires of the outlet switch, etc. can be easily blotched with paint; (6) a workman may easily get paint on his hands when the tape is removed; PA1 (7) there is a fire hazard created by shreds of removed tape left in the electrical box.